A practical soil-structure interaction model for a wind turbine subjected to seismic loads and emergency shutdown

Abstract

In seismically active areas the design of wind turbine must be verified for seismic load combinations. These consider a certain likelihood of earthquake occurrence during normal operation, which could eventually lead to an emergency stop. In order to simulate these scenarios, the computational model should take into account the aerodynamics of the rotor, the flexibility of tower and soil, transient operational phases and, first and foremost, the interrelation of all these aspects. At the same time, the complexity should be reduced in order to avoid enormous computational costs, especially when the soil-structure interaction is taken into account. This study presents a practical model for the analysis of the soil-structure interaction effects on the seismic behavior of wind turbine, during normal power production and emergency shutdown. The presented model is based on simplified lumped parameter model for the soil-foundation subsystem and is validated against a detailed model, based on a 3D coupled finite element method and scaled boundary finite element method approach. This article shows a demonstrative example for a reference 5MW wind turbine subjected to a seismic event which triggers an emergency shutdown. The application of the lumped parameter model allows a significant model size reduction and accurate approximation of the soil-structure behavior in time domain.